Ambient condition detection systems for supervising one or more conditions in a selected region are known. One such system is disclosed and claimed in U.S. Pat. No. 5,539,389, entitled "Enhanced Group Addressing System", assigned to the assignee hereof. The disclosure of the '389 patent is incorporated herein by reference.
Ambient condition systems of the type disclosed in the '389 patent can be configured to detect, in one embodiment, fire profiles based on detected ambient conditions such as smoke, temperature or gas. In such fire detecting systems, it is known to provide audible and visible outputs, horns and strobe lights. These devices can be used to provide human perceptible indications of the presence of a detected fire profile. In this regard, voice annunciation systems have also been used. In such systems, audible messages can be prestored and played back at appropriate times to provide yet another form of communication for individuals in the region being supervised.
Where such annunciation systems are provided, it is desirable to be able to test same without alarming any individuals in the region where the test is being conducted. Preferably such testing could include not only annunciation system circuitry but also associated audio output cables. Also, it would be preferable if such supervision circuitry could be implemented without adding significantly to the cost or complexity of the associated system.